Vitamin A deficiency (VAD) is a major public health problem in low and middle income countries affecting 190 million children under 5 years of age. VAD pre-disposes children to increased risk of a range of problems, including respiratory diseases, diarrhoea, measles and vision problems, and can lead to death.
This review, including 43 randomised trials representing 215,633 children, shows that giving vitamin A capsules to children aged 6 months to 5 years can reduce death and some diseases. The results of 17 of the studies were summarised and indicate that vitamin A reduces the overall risk of death by 24%. Death due to measles, respiratory infections or meningitis was not specifically reduced, but vitamin A can reduce new occurrences of diarrhoea and measles. When people take very large doses of vitamin A, they may be more likely to vomit within two days of taking it.
VAS is effective in reducing all-cause mortality and we recommend universal supplementation for children under 5 in areas at risk of VAD. Further placebo-controlled trials of VAS in children between 6 months and 5 years of age are unnecessary, although studies that compare different doses and delivery mechanisms are needed.
Vitamin A deficiency (VAD) is a major public health problem in low and middle income countries affecting 190 million children under 5. VAD can lead to many adverse health consequences, including death.
To evaluate the effect of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged 6 months to 5 years.
We searched CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE (1950 to April Week 2 2010), EMBASE (1980 to 2010 Week 16), Global Health (1973 to March 2010), Latin American and Caribbean Health Sciences (LILACS), metaRegister of Controlled Trials and African Index Medicus (27 April 2010).
Randomised controlled trials (RCTs) and cluster RCTs evaluating the effect of synthetic VAS in children aged 6 months to 5 years living in the community. We excluded studies of children in hospital and children with disease or infection. We excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods or beta-carotene supplementation.
Two authors independently assessed studies for inclusion. Data were double abstracted and discrepancies resolved by discussion. Meta-analyses were performed for outcomes including all-cause and cause-specific mortality, disease, vision, and side-effects.
Forty-three trials involving 215,633 children were included. A meta-analysis for all-cause mortality included 17 trials (194,795 children). At follow-up, there was a 24% observed reduction in the risk of all-cause mortality for vitamin A compared with control (Relative risk (RR) = 0.76 (95% confidence interval (CI) 0.69 to 0.83). Seven trials reported diarrhoea mortality and showed a 28% overall reduction for VAS (RR = 0.72 (95% CI 0.57 to 0.91)). There was no significant effect of VAS on cause specific mortality of measles, respiratory disease and meningitis. VAS reduced incidence of diarrhoea (RR = 0.85 (95% CI 0.82 to 0.87)) and measles morbidity (RR = 0.50 (95% CI 0.37 to 0.67)); however, there was no significant effect on incidence of respiratory disease or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR = 2.75 (95% CI 1.81 to 4.19)).